Media captionFurther snow and sleet are predicted as the week continues, along with widespread frost and ice

More than 5,000 schools were closed across the UK as snow and icy conditions continued for a fourth day.

Travel has also been affected, with disruption to road and rail journeys.

Gatwick's chief executive criticised Heathrow Airport after it cancelled more than 200 flights. He called for a "better way" to run London airports.

Snow is falling in northern England and southern and eastern Scotland, where the Met Office has amber "be prepared" warnings in force.

And the Environment Agency has issued one flood warning - meaning flooding is expected and immediate action is required - in Somerset, ahead of a "mix of snow, sleet or possibly rain" expected to hit south-west England on Monday evening.

Some 30 flood alerts are also in place across parts of northern and southern England, warning people to be prepared as "flooding is possible".

About one in six schools is thought to have been affected by the weather.

Education Secretary Michael Gove said "everything can and should be done" to keep schools open where possible.

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He told MPs the government had made changes so no school which stayed open would be penalised if individual students could not make it to school on that day.

"And I hope as a result that more and more schools will recognise that, while the decision to remain open or closed is a matter for the headteacher, everything can and should be done in order to ensure that all children get access to a good education."

Forecasters say they expect 10-20cm (4-8in) of snow to fall during Monday in the "amber" areas - and even more on higher ground, with blizzard conditions in some areas. They are also warning of ice affecting East Anglia, southern England and south Wales.

On the rail network, there have been delays on a number of routes, with Greater Anglia, South West Trains, First Capital Connect, London Midland, Southern, East Coast, Virgin and Southeastern services reporting delays, and there are also revised services on the Gatwick Express, the Stansted Express and Eurostar

Train services between Birmingham and Cheltenham have been suspended due to a line blockage, with southbound trains being returned to Birmingham

The Army was called in to help when two buses got stuck in snow in Northumberland, leaving passengers stranded for hours

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Flights continued to be affected by the snow. Heathrow airport has spent millions improving its winter resilience in recent years, but it says low visibility means it must leave more time between planes, triggering delays and cancellations. Manchester, London City and Doncaster all also reported delays.

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Snow which affected the southern half of England on Sunday moved north through the night. Forecasters say the snow will ease into Tuesday, but say widespread frost and ice is likely to affect the UK for much of the week.

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Horse Guards Parade in central London was covered with snow in the morning. Many transport routes into the capital were also affected by the weather.

Gatwick Airport has criticised the number of "pre-emptive flight cancellations at Heathrow", due to what it calls "small amounts of snow", and called for a "better way" to run London airports.

The airport's chief executive, Stewart Wingate, said: "I am proposing that for the key winter months of December, January and February, Heathrow declares a level of capacity it can cope with in winter conditions. The additional flights then, for those three months, can move to Gatwick and Stansted.

"As a result there would be better use of the existing capacity at our London airports, safety would be enhanced and passengers will not have to panic every time it snows. London's and the UK's reputation is on the line and the airports should work together to make this happen."

In response, Heathrow - which had 202 cancellations on Monday - said the Airports Commission had been set up by ministers to examine the issues of UK airport capacity and it was "for the commission to make recommendations for how the shortage of UK hub capacity should be addressed and to consider all options".

Media captionAndy Yeomans from the RAC gives some tips on how to drive in the snow

Other airports, including Gatwick and Birmingham, have also experienced disruption to flights, while flights at Leeds Bradford Airport remain disrupted.